Premium
Simultaneous Cation/Anion Coordination by Bifunctional 1,2‐Diimine/1,2‐Diamine Type Ligands: Synthesis, Structures, and Properties of Tight Ion Pair Complexes of Ruthenium and Iron
Author(s) -
Rau Sven,
Böttcher Lars,
Schebesta Sebastian,
Stollenz Michael,
Görls Helmar,
Walther Dirk
Publication year - 2002
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200211)2002:11<2800::aid-ejic2800>3.0.co;2-e
Subject(s) - chemistry , diimine , amidine , medicinal chemistry , diamine , ligand (biochemistry) , ruthenium , bifunctional , oxalic acid , chloride , carboxylate , moiety , stereochemistry , inorganic chemistry , polymer chemistry , organic chemistry , catalysis , biochemistry , receptor
The reaction between [(η 6 ‐ p ‐cymene)RuCl 2 ] 2 and tetra‐ p ‐tolyloxalic amidine ( oxam1 ) results in a coupled cation/anion coordination forming the ion‐paired complex [(η 6 ‐ p ‐cymene)RuCl( oxam1 )Cl] ( 1a ). According to an X‐ray single crystal diffraction analysis the Ru moiety is coordinated at the 1,2‐diimine part yielding a five‐membered chelate ring. Furthermore, the 1,2‐diamine group on the opposite side binds to a chloride anion via two N−H groups. Exchange of the chloride anion by trifluoractetate yields [(η 6 ‐ p ‐cymene)RuCl( oxam1 )CF 3 CO 2 ] ( 1c ) in which the C=O group is bonded to the diamine part. Similarly, bis(mesityl)bis(pyridylmethyl)oxalic amidine ( oxam2 ) reacts with FeX 2 to yield the ion‐paired complexes 3a (X: Cl), and 3b (X: Br). X‐ray diffraction studies of both compounds reveal that the oxalic amidine ligand acts as a four‐dentate chelating ligand. One halide is fixed in the same way as in 1a . The complex 1a reacts with Pd(acac) 2 (acac: acetylacetonate) to give the tetranuclear heterobimetallic complex [(η 6 ‐ p ‐cymene)RuCl( oxam1 )PdCl] 2 ( 2 ). The related complexes [(tbbpy) 2 Ru(bbimH 2 )(OOC−CF 3 )](PF 6 ) ( 4 ), [(tbbpy) 2 Ru(bbimH 2 ){OOC(CF 2 ) 7 CF 3 })][OOC(CF 2 ) 7 CF 3 ] ( 5 ), [{(tbbpy) 2 Ru(bbimH 2 )} 2 (OOC−C 6 F 4 −COO)](PF 6 ) 2 ( 6 ), and [{(tbbpy) 2 Ru(bbimH 2 )} 2 (OOC−C 6 F 4 −COO)] ( 7 ), (bbimH 2 : bibenzimidazole; tbbpy: 4,4′‐di‐ tert ‐butyl‐2,2′‐bipyridine) also form ion‐paired compounds. According to the X‐ray diffraction analyses of 4−6 both oxygen atoms of the carboxylate ions are coordinated to the two N−H functions via strong N−H ··· O bonds. Although 5 contains a dication, the compound is soluble in solvents of low polarity, even in supercritical carbon dioxide. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)